1. Technical Field
The present invention relates to telecommunications systems and more particularly, but not exclusively, to switches (exchanges), network management systems, fault location methods and billing and charging arrangements for such systems.
2. Related Art
Public switched telephone networks (PSTN) determine charging for calls on the basis of the duration of the call and/or the time at which a call through the network is answered by the called node. The billing of calls is accordingly dependent on the integrity of the analogue network even where sophisticated switching is used between the calling customer node and the destination node. The majority of the so-called local loop, that is the last leg between the destination exchange node and the customer premises, still comprises copper wire pairs and ways have been found to make increasing use of these pairs to provide complex services and multiple line services to customers.
Thus any fault in the local loop may result in deterioration of the quality of service to customers and potentially to customers being billed for ineffective communications calls. It is important for faults in the local loop to be identified at the earliest possible time so that corrective action may be taken before customer perception of quality of service deteriorates and to avoid potential regulatory conflict in connection with apparent billing accuracy.